diff options
Diffstat (limited to 'src/compiler/scala/tools/nsc/backend/jvm/GenASM.scala')
| -rw-r--r-- | src/compiler/scala/tools/nsc/backend/jvm/GenASM.scala | 59 |
1 files changed, 25 insertions, 34 deletions
diff --git a/src/compiler/scala/tools/nsc/backend/jvm/GenASM.scala b/src/compiler/scala/tools/nsc/backend/jvm/GenASM.scala index 388efb4625..4a3d1805d9 100644 --- a/src/compiler/scala/tools/nsc/backend/jvm/GenASM.scala +++ b/src/compiler/scala/tools/nsc/backend/jvm/GenASM.scala @@ -72,19 +72,10 @@ abstract class GenASM extends SubComponent with BytecodeWriters with GenJVMASM { new DirectToJarfileWriter(f.file) case _ => - import scala.tools.util.Javap - if (settings.Ygenjavap.isDefault) { - if(settings.Ydumpclasses.isDefault) - new ClassBytecodeWriter { } - else - new ClassBytecodeWriter with DumpBytecodeWriter { } - } - else if (Javap.isAvailable()) new ClassBytecodeWriter with JavapBytecodeWriter { } - else { - warning("No javap on classpath, skipping javap output.") + if (settings.Ydumpclasses.isDefault) new ClassBytecodeWriter { } - } - + else + new ClassBytecodeWriter with DumpBytecodeWriter { } // TODO A ScalapBytecodeWriter could take asm.util.Textifier as starting point. // Three areas where javap ouput is less than ideal (e.g. when comparing versions of the same classfile) are: // (a) unreadable pickle; @@ -2519,7 +2510,7 @@ abstract class GenASM extends SubComponent with BytecodeWriters with GenJVMASM { if (nextBlock != whereto) jcode goTo labels(whereto) // SI-6102: Determine whether eliding this JUMP results in an empty range being covered by some EH. - // If so, emit a NOP in place of the elided JUMP, to avoid "java.lang.ClassFormatError: Illegal exception table range" + // If so, emit a NOP in place of the elided JUMP, to avoid "java.lang.ClassFormatError: Illegal exception table range" else if (newNormal.isJumpOnly(b) && m.exh.exists(eh => eh.covers(b))) { debugwarn("Had a jump only block that wasn't collapsed") emit(asm.Opcodes.NOP) @@ -3084,7 +3075,7 @@ abstract class GenASM extends SubComponent with BytecodeWriters with GenJVMASM { assert(nonICode.hasNext, "empty block") nonICode.next.isInstanceOf[JUMP] } - + /** * Returns the list of instructions in a block that follow all ICode only instructions, * where an ICode only instruction is one that won't make it to the JVM @@ -3101,7 +3092,7 @@ abstract class GenASM extends SubComponent with BytecodeWriters with GenJVMASM { * Returns the target of a block that is "jump only" which is defined * as being a block that consists only of 0 or more instructions that * won't make it to the JVM followed by a JUMP. - * + * * @param b The basic block to examine * @return Some(target) if b is a "jump only" block or None if it's not */ @@ -3150,12 +3141,12 @@ abstract class GenASM extends SubComponent with BytecodeWriters with GenJVMASM { def rephraseGotos(detour: mutable.Map[BasicBlock, BasicBlock]) { def lookup(b: BasicBlock) = detour.getOrElse(b, b) - + m.code.startBlock = lookup(m.code.startBlock) - + for(eh <- m.exh) eh.setStartBlock(lookup(eh.startBlock)) - + for (b <- m.blocks) { def replaceLastInstruction(i: Instruction) = { if (b.lastInstruction != i) { @@ -3164,18 +3155,18 @@ abstract class GenASM extends SubComponent with BytecodeWriters with GenJVMASM { b.replaceInstruction(idxLast, i) } } - + b.lastInstruction match { case JUMP(whereto) => replaceLastInstruction(JUMP(lookup(whereto))) case CJUMP(succ, fail, cond, kind) => replaceLastInstruction(CJUMP(lookup(succ), lookup(fail), cond, kind)) - case CZJUMP(succ, fail, cond, kind) => + case CZJUMP(succ, fail, cond, kind) => replaceLastInstruction(CZJUMP(lookup(succ), lookup(fail), cond, kind)) case SWITCH(tags, labels) => val newLabels = (labels map lookup) replaceLastInstruction(SWITCH(tags, newLabels)) - case _ => () + case _ => () } } } @@ -3203,7 +3194,7 @@ abstract class GenASM extends SubComponent with BytecodeWriters with GenJVMASM { // blocks for (key <- detour.keySet) { // we use the Robert Floyd's classic Tortoise and Hare algorithm - @tailrec + @tailrec def findDestination(tortoise: BasicBlock, hare: BasicBlock): BasicBlock = { if (tortoise == hare) // cycle detected, map key to key @@ -3227,7 +3218,7 @@ abstract class GenASM extends SubComponent with BytecodeWriters with GenJVMASM { } detour } - + val detour = computeDetour rephraseGotos(detour) @@ -3235,33 +3226,33 @@ abstract class GenASM extends SubComponent with BytecodeWriters with GenJVMASM { val (remappings, cycles) = detour partition {case (source, target) => source != target} for ((source, target) <- remappings) { debuglog(s"Will elide jump only block $source because it can be jumped around to get to $target.") - if (m.startBlock == source) debugwarn("startBlock should have been re-wired by now") + if (m.startBlock == source) debugwarn("startBlock should have been re-wired by now") } val sources = remappings.keySet val targets = remappings.values.toSet val intersection = sources intersect targets - + if (intersection.nonEmpty) debugwarn(s"contradiction: we seem to have some source and target overlap in blocks ${intersection.mkString}. Map was ${detour.mkString}") - + for ((source, _) <- cycles) { debuglog(s"Block $source is in a do-nothing infinite loop. Did the user write 'while(true){}'?") } } } - + /** * Removes all blocks that are unreachable in a method using a standard reachability analysis. */ def elimUnreachableBlocks(m: IMethod) { - assert(m.hasCode, "code-less method") - + assert(m.hasCode, "code-less method") + // assume nothing is reachable until we prove it can be reached val reachable = mutable.Set[BasicBlock]() - + // the set of blocks that we know are reachable but have // yet to be marked reachable, initially only the start block val worklist = mutable.Set(m.startBlock) - + while (worklist.nonEmpty) { val block = worklist.head worklist remove block @@ -3271,7 +3262,7 @@ abstract class GenASM extends SubComponent with BytecodeWriters with GenJVMASM { // think are unreachable worklist ++= (block.successors filterNot reachable) } - + // exception handlers need to be told not to cover unreachable blocks // and exception handlers that no longer cover any blocks need to be // removed entirely @@ -3282,9 +3273,9 @@ abstract class GenASM extends SubComponent with BytecodeWriters with GenJVMASM { unusedExceptionHandlers += exh } } - + // remove the unusued exception handler references - if (settings.debug.value) + if (settings.debug.value) for (exh <- unusedExceptionHandlers) debuglog(s"eliding exception handler $exh because it does not cover any reachable blocks") m.exh = m.exh filterNot unusedExceptionHandlers |